CN114588904A - Cu-based metal oxide catalyst, preparation method thereof and synthesis method of 2,3-butanediol using same - Google Patents

Cu-based metal oxide catalyst, preparation method thereof and synthesis method of 2,3-butanediol using same Download PDF

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CN114588904A
CN114588904A CN202210220303.9A CN202210220303A CN114588904A CN 114588904 A CN114588904 A CN 114588904A CN 202210220303 A CN202210220303 A CN 202210220303A CN 114588904 A CN114588904 A CN 114588904A
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salt
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oxide catalyst
metal oxide
butanediol
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徐国强
王修云
刘秀云
郭星翠
孙孟清
赵玲玲
蒋士峰
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Qingdao Institute of Bioenergy and Bioprocess Technology of CAS
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    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/72—Copper
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    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/78—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with alkali- or alkaline earth metals
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    • B01J37/08—Heat treatment
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    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
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    • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
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    • C07C29/34—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring increasing the number of carbon atoms by reactions without formation of -OH groups by condensation involving hydroxy groups or the mineral ester groups derived therefrom, e.g. Guerbet reaction
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    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/584—Recycling of catalysts

Abstract

Disclosed are a Cu-based metal oxide catalyst, a method for preparing the same, and a method for synthesizing 2,3-butanediol using the same. The preparation method comprises (1) preparing mixed aqueous solution of copper salt, magnesium salt or calcium salt and first metal A salt; (2) dropwise adding the mixed water solution into a carbonate water solution or an alkali solution, then dropwise adding an alkali solution to adjust the pH value of the system, then continuously stirring, standing for aging, then filtering, washing to be neutral, and drying; and (3) roasting the product obtained in the step (2) at the temperature of 500-600 ℃ for 3-12 hours in an air atmosphere to obtain the Cu-based metal oxide catalyst. The preparation method is simple and rapid, simple in process, economical, pollution-free and convenient to operate. The catalyst can not only obviously improve the selectivity and yield of the product. The synthesis method of the 2,3-butanediol has simple process and mild condition, and obviously improves the selectivity of the 2, 3-butanediol.

Description

Cu-based metal oxide catalyst, preparation method thereof and synthesis method of 2,3-butanediol using same
The technical field is as follows:
the application belongs to the field of inorganic catalysts, and particularly relates to a Cu-based metal oxide catalyst, a preparation method thereof and a method for synthesizing 2,3-butanediol by adopting the Cu-based metal oxide catalyst.
Background art:
layered Double Hydroxides (LDHs), also called anionic clay compounds, are the general names of natural and artificially synthesized hydrotalcites and hydrotalcite-like compounds, and are typical anionic host-guest Layered structure compounds, the most prominent characteristic is that the LDHs have a host Layered plate structure and the interchangeability of interlayer ions, and the characteristic can be utilized to realize the modulation of the Layered plate metal ions and the introduction of functional guest intercalation into interlayer gaps, thereby forming a series of novel supermolecule composite functional materials. Most of LDHs have structures close to hydrotalcite, and the molecular formula is Mg6Al2(OH)16CO3·4H2O, and is naturally present in the fiber. Structural characteristics based on hydrotalcite-like compounds, and other complex metal oxides MgO-ZrO2The alkaline earth metal oxides such as CaO and MgO are commonly used as a carrier of the catalyst, and a series of Metal Mixed Oxides (MMO) are prepared by freely combining Cu, Mg, Al, Zr and Ca elements. Compared with the commonly used heterogeneous catalysts, the ternary Mixed Metal Oxide (MMO) has a similar structure to the hydrotalcite system, and has the advantage of being reproducible and stable over a wide temperature range.
Su rez DR, Zeifert BH, 2007,
Figure BDA0003536879470000011
Studies by MH et al report copper hydrotalcite like compounds: morphological, structural and microstructural characteristics-hydrotalcite consists of brucite-like [ Mg (OH)2]Sheet formation of Mg therein2+By trivalent cations (e.g. Al)3+) Partial isomorphous substitution occurs, with excess positive charges in the layers being compensated by anions that occupy the interlayer space together with water molecules. When the nature of the interlayer cations and anions changes, the compound is called a hydrotalcite-like compound (HTLC), and has a wide range of uses in adsorption and catalysis. These compounds are represented by the general formula [ M ]2+ 1-xM3+ x(OH)2]x+(An-)x/n·mH2O represents, wherein M2+And M3+Is a divalent or trivalent cation, x is M2+/(M2++M3+) Ratio of (A)n-Is an interlayer anion having a charge number n. Lee G, Kang JY, Yan N et Al have related research reports in a simple preparation method of Mg-Al hydrotalcite as an alkali catalyst. The structure of the compound is made of positive charge brucite-like M2+(OH)2The laminated plate consists of interlayer exchangeable anions and water molecules, wherein the exchangeable anions exist in the form of hydrated anions. Studies by Kagunya W, Hassan Z, Jones W have reported the catalytic properties of layered double hydroxides and their calcined derivatives. The LDHs host and the LDHs object are connected by weak chemical bonds such as electrostatic attraction, hydrogen bonds or Van der Waals force, and the host and the LDHs object are arranged in a very ordered manner. This particular structure allows the host layers to be easily propped or exfoliated by the guest without affecting the laminate structure, and thus, the LDHs exhibit intercalation and assembly properties. The functional inorganic and organic anion intercalated hydrotalcite is widely applied to heterogenization of homogeneous phase reaction catalyst, immobilization of catalyst, improvement of catalyst stability and the like. It has been reported that anions of different charges and sizes lead to variations in the position and intensity of the series of characteristic diffraction peaks of the intercalated structure LDHs. Miyata and Kumura et al synthesized a series of terminal linear chainsType fatty dicarboxylic acid anion CnH2n(CO2 -)2And (3) intercalation ZnAl-LDHs. Changes in charge density of the LDHs laminates can also cause changes in the arrangement of interlayer guest molecules, which in turn affects the layer spacing. Libo et al analyzed the crystal structure of dodecylsulfonate intercalated MgAl-LDH using XRD techniques. Olsz Lou wka JE, Karcz R, Biela ń ska E et al, in 2018, reported new insights on the preferable valence of interlayer anions of hydrotalcite-like compounds: influence of the Mg/Al ratio. The composite oxide type solid base is usually prepared by roasting LDHs (layered double hydroxides) serving as precursors, such as hydrotalcite and Mg-Al anionic layered compounds with hydrotalcite structures, wherein the layered compounds are prepared by roasting LDHs serving as precursors, are mesoporous materials, and have strong basicity, large specific surface area, high stability and adjustability of structure and basicity.
2,3-butanediol (2, 3-butandediol) with molecular formula C4H10O2The product is colorless viscous liquid, and is crystal at low temperature. Is miscible with water, and is soluble in alcohol and ether. 2,3-butanediol is a compound with high added value, is widely applied to the fields of food, chemical industry, energy and the like, and is mainly produced by a biotransformation method at present. 2,3-butanediol and derivatives thereof are used as important liquid fuels and chemical raw materials, and have wide industrial application prospect. Most production methods of 2,3-butanediol have a problem of safety and a high product separation cost. For example, the biotechnological production progress of 2,3-butanediol is reviewed by thejiangying and the like, the energy consumption of the existing separation process is large, the production cost of the 2,3-butanediol is still relatively high, and the application in various fields is not scaled (research progress of 2,3-butanediol as a bio-based chemical, proceedings of process engineering, 2010, 10(1), 200-. The 2,3-butanediol is widely applied to the fields of food, chemical industry, energy and the like.
Therefore, it is required to develop a suitable catalyst and a method for synthesizing 2,3-butanediol using the catalyst.
The invention content is as follows:
in view of the above-mentioned deficiencies of the prior art, it is an object of the present application to provide a Cu-based metal oxide catalyst. The Cu-based metal oxide catalyst is used for catalyzing the reaction for synthesizing 2,3-butanediol, the selectivity and the yield of a product can be remarkably improved, and the activity and the structure of the catalyst are remarkably improved by changing the proportion of metal atoms in an oxide.
Another object of the present application is to provide a method for preparing the above Cu-based metal oxide catalyst. The preparation method is simple and rapid, simple in process, economical, pollution-free and convenient to operate, and the prepared catalyst can be repeatedly used without obviously reducing the activity.
It is still another object of the present application to provide a method for synthesizing 2,3-butanediol using the above Cu-based metal oxide catalyst. The method has simple process and mild conditions, and obviously improves the selectivity of the 2, 3-butanediol.
In order to achieve the above object, in a first aspect, the present application provides a method for preparing a Cu-based metal oxide catalyst, comprising the steps of:
(1) preparing a mixed aqueous solution of a copper salt, a magnesium salt or a calcium salt and a first metal A salt, wherein the first metal A salt is a salt of a divalent or trivalent metal ion; wherein the molar ratio of Mg or Ca to the first metal A is 1.4-6, and the molar weight of Cu is 2-60% of the total molar weight of all metal ions;
(2) dropwise adding the metal salt mixed water solution prepared in the step (1) into a carbonate water solution or an alkali solution at the temperature of 60-70 ℃, dropwise adding the alkali solution to adjust the pH value of the system to 9.5-10.5, preferably 10, continuously stirring at room temperature for 1-5 hours, standing and aging for 18-30 hours, preferably 24 hours, filtering and washing to be neutral, and drying at the temperature of 100-120 ℃ for 12-24 hours; and
(3) roasting the product obtained in the step (2) at the temperature of 500-600 ℃ for 3-12 hours in air atmosphere to obtain the Cu-based metal oxide catalyst CuyMgmAnOxOr CuyCamAnOxWherein the ratio of m/n is 1.4-6, y/(m + n + y) is 0.02-0.6, and x is the chemical oxygen demand of the stoichiometric ratio.
In a possible embodiment in combination with the first aspect, in the step (1), when copper salts and magnesium salts are used, the first metal a salt is at least one selected from Ca salts, Al salts, and Zr salts; when a copper salt and a calcium salt are used, the first metal A salt is at least one selected from an Al salt and a Zr salt.
In a possible embodiment in combination with the first aspect, the copper, magnesium, Ca and first metal a salts are preferably nitrates.
In a possible embodiment, in combination with the first aspect, the formulation process of step (1) is performed at 60 ℃ to 70 ℃.
In combination with the first aspect, in a possible embodiment, in the step (2), the carbonate in the aqueous carbonate solution is at least one selected from sodium carbonate or potassium carbonate, and is preferably sodium carbonate, and the mixed aqueous metal salt solution is added dropwise to the aqueous carbonate solution so that the molar concentration of carbonate in the system is 0.5 to 10 times the total molar concentration of metal ions.
In combination with the first aspect, in a possible embodiment, in the step (2), the alkali in the alkali solution is at least one selected from sodium hydroxide or potassium hydroxide, and is preferably sodium hydroxide, and OH in the alkali solution-The molar concentration of the ions is 1-10 times of the total molar concentration of the metal ions in the mixed water solution.
In a possible embodiment in combination with the first aspect, in the step (2), the pH of the system is preferably adjusted to 10.
In a possible embodiment in combination with the first aspect, in the step (2), the standing and aging time is preferably 24 hours.
In one possible embodiment, with reference to the first aspect, the method for preparing the Cu-based metal oxide catalyst further includes: in the step (3), the product obtained by roasting is reduced in a hydrogen atmosphere at 300 to 400 ℃ for 2.5 to 3.5 hours, preferably 3 hours, and then the Cu-based metal oxide catalyst is obtained.
In a second aspect, the present application provides a Cu-based metal oxide catalyst produced by the above-described method for producing a Cu-based metal oxide catalyst.
In a third aspect, the present application provides a method for synthesizing 2,3-butanediol using the above Cu-based metal oxide catalyst, comprising:
in the presence of the Cu-based metal oxide catalyst and in a hydrogen atmosphere, carrying out intermittent high-pressure reaction on methanol and 1, 2-propylene glycol for 3-5 hours under the conditions that the gas pressure is 1-3 MPa and the reaction temperature is 190-210 ℃ to obtain the 2, 3-butanediol.
In a possible embodiment, in combination with the third aspect, the 1, 2-propanediol represents 2.5% to 35%, preferably 7.5% to 15%, by weight of the total weight of the mixture of methanol and 1, 2-propanediol.
In combination with the third aspect, in one possible embodiment, the reaction temperature is preferably 210 ℃.
According to the technical scheme provided by the application, compared with the prior art, the method at least comprises the following beneficial effects:
the present application provides Cu-based metal oxide catalysts and methods of making the same. The Cu-based metal oxide catalyst is used for catalyzing the reaction for synthesizing 2,3-butanediol, has a stable structure, more uniform acid and alkali active sites and better acid and alkali resistance, and has greater potential in catalyzing the condensation of methanol and 1, 2-propanediol to prepare 2, 3-butanediol. The catalyst not only can obviously improve the selectivity and yield of the product, but also can obviously improve the activity and structure of the catalyst by changing the proportion of metal atoms in the oxide. The preparation method is simple and rapid, simple in process, economical, pollution-free and convenient to operate, and the prepared catalyst can be repeatedly used without obviously reducing the activity. In addition, the selectivity of the 2,3-butanediol is obviously improved within the range of the element ratio of the mixed metal oxide.
The application also provides a synthesis method for preparing 2,3-butanediol by catalyzing direct condensation of methanol and 1, 2-propanediol by using the Cu-based metal oxide catalyst. The method has simple reaction process and mild conditions.
Drawings
FIG. 1 shows two main routes for the condensation reaction of methanol and 1, 2-propanediol.
FIG. 2 shows the reaction steps for the synthesis of 2,3-butanediol by the reaction of methanol with 1, 2-propanediol.
Fig. 3 is a graph showing adsorption and desorption curves and pore size distribution of four CuMgAl mixed oxide catalysts prepared according to examples 1-2 of the present application using sodium carbonate aqueous solutions of different concentrations as a precipitant.
FIG. 4 is an XRD pattern of four CuMgAl mixed oxides prepared according to examples 1-2 of the present application using different concentrations of aqueous sodium carbonate as a precipitant
FIG. 5 shows the molar ratio of Mg to Al to Cu atoms 12:4: SEM image of Cu-based metal oxide catalyst (Gr-CuMgAl) of 3.
FIG. 6 is NH for CuCaZr (example 10), CuMgCaOx (example 3-1), CuMgZr (example 2) and CuMgAl (example 1-1) catalysts3-TPD。
Fig. 7 is an XRD phase analysis before and after reaction of the CuMgCaOx catalyst prepared by the co-precipitation method according to examples 3-3 of the present application.
FIG. 8 shows a molar ratio of Mg to Ca to Cu atoms of 12:8:3 (upper row) and the molar ratio of Mg: Ca: Cu atoms prepared in examples 3 to 4, 8: 13: SEM image of Cu-based metal oxide catalyst of 3 (next row).
FIG. 9 is a TEM image of a Cu-based metal oxide catalyst of CuMgCaOx (Mg: Ca: Cu atoms in a molar ratio of 12:8: 3) prepared according to example 3-1 of the present application.
Detailed Description
In order that those skilled in the art will be able to more clearly understand the present application, the present application will be described in detail below with reference to examples. Before the description is made, it should be understood that the terms used in the present specification and the appended claims should not be construed as limited to general and dictionary meanings, but interpreted based on the meanings and concepts corresponding to technical aspects of the present application on the basis of the principle that the inventor is allowed to define terms appropriately for the best explanation. Accordingly, the description proposed herein is just a preferable example for the purpose of illustrations only, not intended to limit the scope of the application, so it should be understood that other equivalents and modifications could be made thereto without departing from the spirit and scope of the application, and the scope of the application claims should be determined only by the claims. Unless otherwise specified, reagents and equipment used in the following examples are commercially available products.
The present application first provides a Cu-based metal oxide catalyst and a method for preparing the same. The preparation method adopts LDHs as a carrier to modify, prepares the Cu-based LDHs catalyst in a coprecipitation-roasting mode, has an L acid-base pair in roasted Mg-metal hydrotalcite, is very favorable for cross condensation reaction, and develops the Cu-based metal oxide catalyst by combining with stronger hydrogenation action of copper so as to be applied to the cross condensation reaction of dihydric alcohol and monohydric alcohol, such as catalyzing the condensation of methanol and 1, 2-propylene glycol to prepare 2, 3-butanediol.
In addition, the application also provides a method for catalytically synthesizing 2,3-butanediol by using the Cu-based metal oxide catalyst. The method mainly obtains a target product through alcohol coupling reaction, and two stereoisomers of 2,3-butanediol and 1, 2-butanediol are obtained through synthesis, wherein the selectivity of 2,3-butanediol is high. The process has the advantages of cheap and easily obtained raw materials, simple operation equipment and process and little environmental pollution.
Specifically, the method is realized through the following technical scheme:
in a first aspect, the present application provides a method for preparing a Cu-based metal oxide catalyst, comprising the steps of:
(1) preparing a mixed aqueous solution of a copper salt, a magnesium salt or a calcium salt and a first metal A salt, wherein the first metal A salt is a salt of divalent or trivalent metal ions, the molar ratio of Mg or Ca to the first metal A is 1.4-6, and the molar content of Cu is 2-60% of the total molar amount of all the metal ions; and
(2) dropwise adding the mixed water solution prepared in the step (1) into a carbonate water solution or an alkali solution at the temperature of 60-70 ℃, dropwise adding the alkali solution to adjust the pH value of the system to 9.5-10.5, continuously stirring at room temperature for 1-5 hours, standing and aging for 18-30 hours, filtering and washing to be neutral, and drying at the temperature of 100-120 ℃ for 12-24 hours;
(3) roasting the product obtained in the step (2) at the temperature of 500-600 ℃ for 3-12 hours in an air atmosphere to obtain the Cu-based metal oxide catalyst CuyMgmAnOxOr CuyCamAnOxWherein the ratio of m/n is 1.4-6, y/(m + n + y) is 0.02-0.6, and x is the chemical oxygen demand of the stoichiometric ratio.
The preparation method of the Cu-based metal oxide catalyst is simple and rapid, simple in process, economical, pollution-free and convenient to operate, and the prepared catalyst can be repeatedly used for many times without obviously reducing the activity.
In a possible embodiment in combination with the first aspect, in the step (1), when copper salts and magnesium salts are used, the first metal a salt is at least one selected from Ca salts, Al salts, and Zr salts; when a copper salt and a calcium salt are used, the first metal A salt is at least one selected from an Al salt and a Zr salt.
In the present application, a series of Cu-based metal oxide catalysts may be synthesized by the above-described preparation method of the catalyst, including a CuMgAl oxide catalyst, a CuMgZr oxide catalyst, a CuMgCaOx oxide catalyst, a CuCaZr oxide catalyst, and the like. Among them, the CuMgAl oxide catalyst and the CuMgCaOx oxide catalyst are preferably higher in activity.
In the step (1), the molar ratio of Mg or Ca to a in the mixed aqueous solution is 1.4 to 6, and may be, for example, 1.4, 1.6, 1.8, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, or 6, or other values within the range. And the molar content of Cu is 2% to 60% of the total molar amount of all metal ions, and may be, for example, 2%, 3%, 10%, 20%, 50%, or 60%, or other values within the range. Within the range of the molar ratio (mole fraction), a Cu-based metal oxide catalyst excellent in performance can be obtained.
In a possible embodiment in combination with the first aspect, the copper salt, the magnesium salt and the first metal a salt are preferably nitrates. Nitrate is adopted, the water solubility of the nitrate is generally good, the nitrate is beneficial to being prepared into solution so as to obtain a precipitation product through a coprecipitation method, and the residual nitrate is easy to remove through water washing.
In a possible embodiment, in combination with the first aspect, the formulation process of step (1) is performed at 60 ℃ to 70 ℃. By formulating the solution at a higher temperature, the solubility of the copper salt, the magnesium salt and the first metal a salt is advantageously increased, facilitating more precipitated product to be obtained subsequently.
In a possible embodiment in combination with the first aspect, in the step (2), the carbonate in the aqueous carbonate solution is at least one selected from sodium carbonate or potassium carbonate, and is preferably sodium carbonate, and the mixed aqueous solution of metal salts is added dropwise to the aqueous carbonate solution so that the molar concentration of carbonate in the system is 0.5 to 10 times of the total molar concentration of metal ions, for example, 0.5 times, 1 time, 1.5 times, 2 times, 2.5 times, 3 times, 3.5 times, 4 times, 4.5 times, 5 times, 5.5 times, 6 times, 6.5 times, 7 times, 7.5 times, 8 times, 8.5 times, 9 times, 9.5 times, or 10 times, or other values in the range. By adopting a carbonate precipitant, layered composite metal hydroxides (LDHs) can be prepared conveniently.
In a possible embodiment in combination with the first aspect, the alkali in the alkali solution is at least one selected from sodium hydroxide or potassium hydroxide, and is preferably sodium hydroxide, and OH in the alkali solution-The molar concentration of the ions is 1 to 10 times of the total molar concentration of the metal ions in the mixed aqueous solution, and may be, for example, 1 time, 1.5 times, 2 times, 2.5 times, 3 times, 3.5 times, 4 times, 4.5 times, 5 times, 5.5 times, 6 times, 6.5 times, 7 times, 7.5 times, 8 times, 8.5 times, 9 times, 9.5 times, or 10 times, or other values within the above range.
In a possible embodiment in combination with the first aspect, in the step (2), the pH of the system is preferably adjusted to 10. The generation of the precipitate can be effectively promoted by controlling the pH value of the system to be 9.5-10.5, preferably 10.
In a possible embodiment, in combination with the first aspect, in the step (2), the standing and aging time is 18 to 30 hours, for example, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, 25 hours, 26 hours, 27 hours, 28 hours, 29 hours, or 30 hours, or other values in the range. Also, the time for the standing aging is preferably 24 hours. The desired precipitated product is conveniently obtained by sufficient standing and aging.
In one possible embodiment, with reference to the first aspect, the method for preparing the Cu-based metal oxide catalyst further includes: in the step (3), the product obtained by roasting is reduced in a hydrogen atmosphere at 300 to 400 ℃ for 2.5 to 3.5 hours, preferably 3 hours, and then the Cu-based metal oxide catalyst is obtained. When the first metal a salt is, for example, an Al salt, the reactivity can be further improved by firing in a hydrogen atmosphere.
In a second aspect, the present application provides a Cu-based metal oxide catalyst produced by the above-described method for producing a Cu-based metal oxide catalyst.
The Cu-based metal oxide catalyst is used for catalyzing the reaction for synthesizing 2,3-butanediol, and not only can the selectivity and the yield of a product be remarkably improved, but also the activity and the structure of the catalyst can be remarkably improved by changing the proportion of metal atoms in the oxide.
In a third aspect, the present application provides a method for synthesizing 2,3-butanediol using the above Cu-based metal oxide catalyst, comprising:
in the presence of the Cu-based metal oxide catalyst and in a hydrogen atmosphere, carrying out intermittent high-pressure reaction on methanol and 1, 2-propylene glycol for 3-5 hours at the gas pressure of 1-3 MPa and the reaction temperature of 190-210 ℃ to obtain 2, 3-butanediol.
According to the synthesis method of the 2,3-butanediol by adopting the Cu-based metal oxide catalyst, the process is simple, the condition is mild, and the selectivity of the 2,3-butanediol is obviously improved.
Further, the gas pressure of the reaction may be 1 to 3MPa, for example, 1MPa, 1.5MPa, 2MPa, 2.5MPa or 3MPa, or other values within the range. By carrying out the reaction at this gas pressure, it is helpful to promote the formation of 2, 3-butanediol.
Further, the reaction time may be 3 to 5 hours, for example, 3 hours, 3.5 hours, 4 hours, 4.5 hours, or 5 hours, or other values within the range. Within this reaction time range, the yield of 2,3-butanediol will be maximized.
In addition, the batch high-pressure reaction may be performed in a batch high-pressure reaction tank, but the present application is not limited thereto.
For the condensation reaction of methanol and 1, 2-propylene glycol, two carbon chain extension reaction paths of 1, 2-propylene glycol in a methanol system are provided, namely C-C bonding is carried out at two ends of 1, 2-propylene glycol respectively, and the main reaction path is shown in figure 1. The reaction belongs to Guerbet (Gerbet) reaction, also called alcohol coupling, is a dehydration process, has high atom utilization rate, is an important way for carbon chain growth reaction of alcohol compounds, and mainly comprises four reaction steps. The carbon chain extension reaction process of 1, 2-propanediol in the methanol system mainly comprises several processes (dehydrogenation, aldol condensation, dehydration and hydrogenation) as shown in fig. 2.
In combination with the third aspect, in one possible embodiment, the weight of 1, 2-propanediol comprises 2.5% to 35% of the total weight of the mixture of methanol and 1, 2-propanediol, for example, 2.5%, 2.6%, 2.7%, 7.5%, 7.6%, 7.7%, 8.0%, 8.5%, 10.1%, 11.1%, 12.5%, 13.5%, 14.9%, 20.5%, 21.5%, 25.5%, 27.5%, 29.5%, or 35%, or other values within the stated range. Within this molar ratio range, conversion of methanol and 1, 2-propanediol and production of 2,3-butanediol are facilitated.
In combination with the third aspect, in one possible embodiment, the reaction temperature may be 190 ℃ to 210 ℃, for example, 190 ℃, 195 ℃, 200 ℃, 205 ℃, or 210 ℃, or other values within the stated range. Also, the reaction temperature is preferably 210 ℃. By carrying out the reaction in this temperature range, it is also helpful to promote the production of 2, 3-butanediol.
The application provides a Cu-based metal oxide catalyst and a preparation method thereof. The Cu-based metal oxide catalyst is used for catalyzing the reaction of synthesizing 2,3-butanediol, has a stable structure, more uniform acid and alkali active sites and better acid and alkali resistance, and has greater potential in catalyzing the condensation of methanol and 1, 2-propanediol to prepare 2, 3-butanediol. The catalyst not only can obviously improve the selectivity and yield of the product, but also can obviously improve the activity and structure of the catalyst by changing the proportion of metal atoms in the oxide. The preparation method is simple and rapid, simple in process, economical, pollution-free and convenient to operate, and the prepared catalyst can be repeatedly used without obviously reducing the activity. In addition, the selectivity of the 2,3-butanediol is obviously improved within the range of the element ratio of the mixed metal oxide.
The application also provides a synthesis method for preparing 2,3-butanediol by catalyzing direct condensation of methanol and 1, 2-propanediol by using the Cu-based metal oxide catalyst. The method has simple reaction process and mild conditions.
Examples
Examples 1 to 1
The Cu-based metal oxide catalyst according to the present application was prepared using the following preparation method:
(1) preparing a mixed aqueous solution (the volume of the mixed solution is about 150mL) from magnesium nitrate, aluminum nitrate and copper nitrate according to a molar ratio of 12:5: 3;
(2) dropwise adding the mixed aqueous solution obtained in step (1) to an aqueous sodium carbonate solution at 65 deg.C to obtain a carbonate concentration of 0.133mol/L, such as 2.63g Na2CO3Dissolving in 187mL water to obtain a solution, wherein the molar concentration of magnesium is 0.06mol/L, the molar concentration of aluminum is 0.025mol/L and the molar concentration of copper is 0.015mol/L, stirring while dropwise adding, then dropwise adding sodium hydroxide solution (1mol/L) to adjust the pH value of the system to 10, then continuing stirring for 1 hour at room temperature, standing and aging for 24 hours, then carrying out suction filtration, and washing the precipitate to neutralityThen, the precipitate is dried for 24 hours at 100 ℃; and
(3) and (3) heating the product obtained in the step (2) to 500 ℃ in a tube furnace, roasting for 7 hours in an air atmosphere to obtain a black solid, and then reducing for 3 hours at 350 ℃ in a hydrogen atmosphere to obtain the CuMgAl oxide catalyst.
The catalyst is used for synthesizing 2, 3-butanediol:
mixing methanol (analytically pure) and 1, 2-propylene glycol (analytically pure), preparing a solution with a certain concentration, putting the solution into a reaction kettle, adding the catalyst prepared by the method, and sealing the reaction kettle. Then, replacing air in the intermittent high-pressure reaction kettle (for multiple times) with nitrogen or hydrogen, putting the reaction kettle into a thermocouple heating sleeve for heating, and setting the reaction time to be 3-5 h. After completion of the reaction, the reaction mixture was cooled to room temperature, and the sample was collected by filtration through a 0.22 μm filter to prepare a sample. 2,3-butanediol, due to its three stereoisomers, including one meso isomer, two peaks appear by gas chromatography (GC-MS) and product conversion and yield are calculated. The experimental conditions and results are shown in table 1 below:
TABLE 1 catalysis conditions and catalytic Effect of CuMgAl catalyst (reactant concentrations refer to 1, 2-propanediol in wt.% of the total mixture of methanol and 1, 2-propanediol)
Figure BDA0003536879470000101
As can be seen from the results in table 1, the catalyst showed higher activity for low concentrations of propylene glycol and substantially maintained selectivity consistent with high concentrations of propylene glycol, with high temperatures favoring conversion for the reaction, but with increased side reactions. Therefore, the CuMgAl catalyst shown in Table 1 can significantly improve the conversion rate and selectivity of the reaction.
Examples 1 to 2
A Cu-based metal oxide catalyst according to the present application was prepared in the same manner as in example 1-1 above, except that aqueous sodium carbonate solutions of different concentrations were used as a precipitant. As shown in FIG. 3, the adsorption-desorption curves and pore size distributions of the prepared CuMgAl (12: 4: 3) oxide catalyst under the conditions of different carbonate concentrations as a precipitator are shown. In the experimental process, for catalysts prepared by precipitants with different concentrations, L-CuMgAl represents a low-concentration precipitator (the molar concentration of carbonate in a system is 0.1mol/L), and the catalysts are roasted at the normal temperature of 550 ℃ without reduction. And Lr-CuMgAl is used for expressing that the catalyst is subjected to reduction roasting at 350 ℃ by using hydrogen on the basis of L-CuMgAl treatment. G-CuMgAl represents a precipitator with higher concentration (the molar concentration of carbonate in the system is 0.5mol/L), and the sintering is carried out at the normal temperature of 550 ℃. The Gr-CuMgAl catalyst is subjected to reduction roasting at 350 ℃ by using hydrogen on the basis of treatment by using G-CuMgAl.
In FIG. 3, Na is present at a high concentration2CO3The CuMgAl catalyst prepared by using the solution as a precipitator has obviously larger aperture than that of a CuMgAl catalyst with low concentration, and mainly takes mesopores (2 nm-50 nm) as a main component. In addition, the adsorption-desorption isotherms of the four catalysts show an adsorption-desorption loop, namely a desorption hysteresis phenomenon, which further proves that the catalysts have capillary pores with different sizes and shapes. High concentration of Na2CO3Catalyst prepared by using solution as precipitator
Figure BDA0003536879470000112
When the adsorption amount is close to 1, the adsorption amount rapidly increases, and a capillary condensation phenomenon occurs. Pressure is close to P0In the process, the adsorption line is steep, and the desorption line is sharply reduced, which is the characteristic of a typical layered mesoporous material.
As shown in fig. 4, which shows a molar ratio of Mg: Al: Cu atoms of 12:4:3 XRD phase analysis of Cu-based metal oxide catalyst. The catalyst pattern in fig. 4 appears to be distinctive: the peak is obviously wider, and the crystal substance can be judged; there are many very narrow peaks independent of each other (2 Theta-0.1 ° to 0.2 °). The particles of crystals in the sample should be crystallites with a size of less than 300 nm.
In FIG. 4a, four catalysts with the same mixture ratio (molar ratio of Mg: Al: Cu atoms is 12:4: 3) prepared by using different carbonate concentrations as precipitating agents are shown, the peaks of the Gr-CuMgAl catalyst are obviously sharpened through XRD comparison of the four catalysts, so that the crystal forms of the catalysts are relatively good, and FIG. 4b shows thatThe phase of the medium Gr-CuMgAl catalyst is mainly hydrated basic carbonate, which indicates that the metal copper in the catalyst is mainly in the form of Cu2+。
As shown in fig. 5, which shows a molar ratio of Mg: Al: Cu atoms of 12:4: SEM image of Cu-based metal oxide catalyst (Gr-CuMgAl) of 3. Under a scanning electron microscope, a lamellar structure is presented, similar to "cotton wool".
Table 2 Gr-CuMgAl in methanol and 1, 2-propanediol, where 7.5% and 15% represent the concentration of 1, 2-propanediol in the total mixture of methanol and 1, 2-propanediol (wt.%), respectively
Figure BDA0003536879470000111
From the results in Table 2, it can be seen that the catalyst exhibits high activity against low and high concentrations of 1, 2-propanediol, the other conditions are unchanged, the conversion of the reaction is facilitated by a hydrogen atmosphere of a suitable pressure, the formation of 1, 2-butanediol is facilitated by a hydrogen atmosphere, but the selectivity of 2,3-butanediol is substantially unchanged.
Example 2
The Cu-based metal oxide catalyst according to the present application was prepared using the following preparation method:
(1) preparing magnesium nitrate, zirconyl nitrate and copper nitrate into a mixed aqueous solution according to a molar ratio of 12:5:3, wherein the molar concentrations of the mixed aqueous solution are 0.06mol/L, 0.025mol/L and 0.015mol/L respectively (the volume of the mixed solution is 150 mL);
(2) dropwise adding the mixed aqueous solution prepared in the step (1) into a sodium carbonate aqueous solution (with the molar concentration of 0.133mol/L) at 65 ℃, stirring while dropwise adding, then dropwise adding a sodium hydroxide solution (1mol/L) to adjust the pH value of the system to 10, then continuously stirring for 1 hour at room temperature, standing and aging for 24 hours, then carrying out suction filtration, washing the precipitate to be neutral, and then placing the precipitate at 100 ℃ for drying for 24 hours; and
(3) and (3) heating the product obtained in the step (2) to 500 ℃ in a tube furnace by a program, roasting for 7 hours in an air atmosphere to obtain a black solid, and then reducing for 3 hours at 350 ℃ in a hydrogen atmosphere to obtain the CuMgZr oxide catalyst.
The catalyst is used for synthesizing 2, 3-butanediol:
mixing methanol (analytically pure) and 1, 2-propylene glycol (analytically pure), preparing a solution with a certain concentration, putting the solution into a reaction kettle, adding the catalyst prepared by the method, and sealing the reaction kettle. Then, replacing air in the intermittent high-pressure reaction kettle (for multiple times) with nitrogen or hydrogen, putting the reaction kettle into a thermocouple heating sleeve for heating, and setting the reaction time to be 3-5 h. After completion of the reaction, the reaction mixture was cooled to room temperature, and the sample was collected by filtration through a 0.22 μm filter. 2,3-butanediol, due to its three stereoisomers, including one meso isomer, two peaks appear by gas chromatography (GC-MS) and product conversion and yield are calculated. The experimental conditions and results are shown in table 2 below:
TABLE 3 comparison of catalytic conditions and catalytic Effect of CuMgZr catalyst with several other catalysts
Figure BDA0003536879470000121
As shown in FIG. 6, NH3-TPD was shown for CuCaZr (example 10), CuMgCaOx (example 3-1), CuMgZr (example 2) and CuMgAl (example 1-1) catalysts prepared according to example 2 of the present application. Wherein CuMgZr has a more obvious desorption peak below 200 ℃, which indicates a weaker acidic site, CuMgZr and CuMgAl have a wider desorption peak at 350-500 ℃, CuMgCaOx has a smaller desorption peak at 200-350 ℃, which indicates a medium acidic site. In summary, these four mixed metal oxides are mesoporous solid catalysts having acidity.
Example 3-1
The Cu-based metal oxide catalyst according to the present application was prepared using the following preparation method:
(1) preparing a mixed aqueous solution from magnesium nitrate, calcium nitrate and copper nitrate according to a molar ratio of 12:8:3, wherein the molar concentrations of the mixed aqueous solution are 0.06mol/L, 0.040mol/L and 0.015mol/L respectively (the volume of the mixed solution is about 150 mL);
(2) dropwise adding the mixed aqueous solution prepared in the step (1) into a sodium carbonate aqueous solution (with the molar concentration of 0.133mol/L) at 65 ℃, stirring while dropwise adding, then dropwise adding a sodium hydroxide solution (1mol/L) to adjust the pH value of the system to 10, then continuously stirring for 1 hour at room temperature, standing and aging for 24 hours, then carrying out suction filtration, washing the precipitate to be neutral, and then placing the precipitate at 100 ℃ for drying for 24 hours; and
(3) heating the product obtained in the step (2) to 650 ℃ in a tube furnace by a program, roasting for 6 hours in an air atmosphere to obtain a black solid, and then reducing for 3 hours at 350 ℃ in a hydrogen atmosphere to obtain CuMgCaOXAn oxide catalyst.
The catalyst is used for synthesizing 2, 3-butanediol:
mixing methanol (analytically pure) and 1, 2-propylene glycol (analytically pure), preparing a solution with a certain concentration, putting the solution into a reaction kettle, adding the catalyst prepared by the method, and sealing the reaction kettle. Then, replacing air in the intermittent high-pressure reaction kettle (for multiple times) with nitrogen or hydrogen, putting the reaction kettle into a thermocouple heating sleeve for heating, and setting the reaction time to be 3-5 h. After completion of the reaction, the reaction mixture was cooled to room temperature, and a sample was taken through a 0.22 μm filter to prepare a sample. 2,3-butanediol, due to its three stereoisomers, including one meso isomer, two peaks appear by gas chromatography (GC-MS) and product conversion and yield are calculated. The experimental conditions and results are shown in table 4 below:
TABLE 4 catalytic conditions and catalytic Effect of CuMgCaOx catalyst
Figure BDA0003536879470000131
Figure BDA0003536879470000141
From the results in table 4, it can be seen that the CuMgCaOx catalyst has better activity in the reaction, and particularly in the hydrogen atmosphere, the selectivity is significantly improved, but the conversion is reduced, and the concentration of the reactant, the reaction atmosphere and the pressure also have an influence on the reaction.
Further, as shown in fig. 8, it is demonstrated that the molar ratio of Mg: Ca: Cu atoms produced is 12:8: SEM image of Cu-based metal oxide catalyst of 3. Observing the appearance of the composite material, the composite material can be seen to have worm-like pore canals which are adhered to each other and have a hollowed-out lamellar structure.
Examples 3 to 2
Except that the molar ratio of Mg to Ca to Cu atoms was 3: 1: except for 1, a Cu-based metal oxide catalyst according to the present application was prepared in the same manner as in the above-described example 3-1. The catalyst was used to synthesize 2,3-butanediol, and the experimental conditions and results are shown in table 5 below:
TABLE 5 catalytic effect of other CuMgCaOx catalytic conditions at 15% (wt.%) concentration of the same feedstock
Figure BDA0003536879470000142
TABLE 6 catalytic Effect of CuMgCaOx on other conditions at the same feed solution concentration (7.5% wt.)
Figure BDA0003536879470000143
From the results in tables 5 and 6, it can be seen that, under the precondition that the content of Mg is higher than that of Cu and Ca, the influence of changing the proportion of the catalyst on the activity is small, and the activity of the catalyst can be effectively improved due to the combination of the catalyst property and the reaction condition.
Examples 3 to 3
Except that the molar ratio of Mg to Ca to Cu atoms was 12:8: in addition, a Cu-based metal oxide catalyst according to the present application was prepared in the same manner as in example 3-1 described above.
As shown in fig. 7, it shows XRD phase analysis of Cu-based metal oxide catalyst with Mg: Ca: Cu molar ratio of 12:8: 3. Wherein a is CuCaMgOxXRD phase diagram of the catalyst before use, bThe three diagrams of c and d are XRD physical phase diagrams after 5h, 10h and 20h of reaction respectively. From the phase-phase analysis, the phase changes before and after the reaction, and the phase is basically constant after the catalyst reacts for 10h and 20 h. As described above, it is preferable to keep the reaction time at about 5 hours. In the catalyst after the reaction, the copper element is mainly changed into a free state from an original oxidation state, and the change of the valence state of the Cu element in the reaction process can be inferred.
Examples 3 to 4
Except that the molar ratio of Mg to Ca to Cu atoms was 8: 13: except for 3, a Cu-based metal oxide catalyst according to the present application was prepared in the same manner as in example 3-1 described above. Referring to FIG. 8, the molar ratio of Mg to Ca to Cu atoms, 12, produced in example 3-1 is shown: 8:3 (upper row) to the molar ratio of Mg: Ca: Cu atoms produced in this example 8: 13: SEM image of Cu-based metal oxide catalyst of 3 (next row). FIG. 9CuMgCaOxTEM images of (Mg: Ca: Cu atom molar ratio 12:8: 3), a, b, c, d are morphologies in different visual field ranges, and the structure is relatively regular as a whole.
TABLE 7 catalyst CuMgCaOx (molar ratio of Mg: Ca: Cu atoms 8: 13: 3)
Figure BDA0003536879470000151
As can be seen from Table 7, it can be determined from the reaction data that an important condition in the preparation of such mixed metal oxides is that the Mg content must be greater than Ca, otherwise the conversion of the reaction feed is affected.
By changing the ratio of Mg/Ca, the structure of the catalyst is influenced by excessive content of Ca, and the proper content of Ca can be favorable for forming a more regular structure to a certain extent.
Example 4
The Cu-based metal oxide catalyst according to the present application was prepared using the following preparation method:
(1) preparing magnesium nitrate, aluminum nitrate and copper nitrate into mixed aqueous solution according to the molar ratio of 12:5:3, wherein the molar concentrations of the mixed aqueous solution are 0.06mol/L, 0.025mol/L and 0.015mol/L respectively (the volume of the mixed solution is about 150 mL);
(2) dropwise adding the mixed aqueous solution prepared in the step (1) into a sodium carbonate aqueous solution (the molar concentration is 0.40mol/L, the mass is 7.95g, and the volume of the solution is about 187mL) at 65 ℃, stirring while dropwise adding, then dropwise adding a sodium hydroxide solution (1mol/L) to adjust the pH value of the system to be 10, then continuously stirring for 1 hour at room temperature, standing and aging for 24 hours, then carrying out suction filtration, washing the precipitate to be neutral, and then placing the precipitate at 100 ℃ for drying for 24 hours; and
(3) and (3) heating the product obtained in the step (2) to 600 ℃ in a tube furnace, and roasting for 6 hours in an air atmosphere to obtain the CuMgAl oxide catalyst.
The catalyst is used for synthesizing 2, 3-butanediol:
2mL of 1, 2-propanediol and 15mL of methanol were added to a batch autoclave, 0.2g of the catalyst prepared by the above method was added, and the autoclave was sealed. Then, the air in the batch type high-pressure reaction kettle is replaced by hydrogen (for multiple times), then the reaction is carried out for 3 hours at the temperature of 210 ℃ under the hydrogen pressure of 2MPa, the reaction is finished and cooled to the room temperature, a filter membrane with the diameter of 0.22 mu m is used for filtering and sampling to prepare a sample, 2,3-butanediol has three stereoisomers, wherein the stereoisomers comprise an internal isomer, the conversion rate of the 1, 2-propanediol is close to 50.9 percent by calculation through qualitative analysis of gas chromatography (GC-MS), and the selectivity of the 2,3-butanediol reaches 54.9 percent.
Example 5
The Cu-based metal oxide catalyst according to the present application was prepared using the following preparation method:
(1) preparing magnesium nitrate, aluminum nitrate and copper nitrate into mixed aqueous solution according to the molar ratio of 12:5:3, wherein the molar concentrations of the mixed aqueous solution are 0.06mol/L, 0.025mol/L and 0.015mol/L respectively (the volume of the mixed solution is about 150 mL);
(2) dropwise adding the sodium hydroxide solution (1mol/L) prepared in the step (1) into the mixed aqueous solution at 65 ℃, stirring while dropwise adding, adjusting the pH value of the system to 10, then continuously stirring for 1 hour at room temperature, standing and aging for 24 hours, then performing suction filtration, washing the precipitate to be neutral, and then placing the precipitate at 100 ℃ for drying for 24 hours; and
(3) and (3) heating the product obtained in the step (2) to 500 ℃ in a tube furnace, roasting for 6 hours in an air atmosphere to obtain a dark brown solid, and then reducing for 3 hours in a hydrogen atmosphere at 400 ℃ to obtain the CuMgAl oxide catalyst.
The catalyst is used for synthesizing 2, 3-butanediol:
2mL of 1, 2-propanediol and 15mL of methanol were added to a batch autoclave, 0.25mL of the reaction intermediate hydroxyacetone was added as an initiator, 0.2g of the catalyst prepared by the above method was added, and the autoclave was sealed. Then, the air in the batch type high-pressure reaction kettle is replaced by hydrogen (for multiple times), then the reaction is carried out for 3 hours at the temperature of 210 ℃ under the hydrogen pressure of 2MPa, the reaction is finished and cooled to room temperature, the sample is filtered and sampled through a filter membrane of 0.22 mu m, a sample is prepared, 2,3-butanediol has three stereoisomers, wherein the stereoisomers comprise one meso isomer, the conversion rate of the 1, 2-propanediol is close to 21.43 percent by calculation through the qualitative analysis of gas chromatography (GC-MS), and the selectivity of the 2,3-butanediol reaches 75.6 percent.
Example 6
The Cu-based metal oxide catalyst according to the present application was prepared using the following preparation method:
(1) preparing magnesium nitrate, aluminum nitrate and copper nitrate into mixed aqueous solution according to the molar ratio of 69:29:2, wherein the molar concentrations are 0.069mol/L, 0.029mol/L and 0.02mol/L respectively (the volume of the mixed solution is about 150 mL);
(2) dropwise adding the mixed aqueous solution prepared in the step (1) into a sodium carbonate aqueous solution (with the molar concentration of 0.133mol/L) at 65 ℃, stirring while dropwise adding, then dropwise adding a sodium hydroxide solution (1mol/L) to adjust the pH value of the system to 10, then continuously stirring for 1 hour at room temperature, standing and aging for 24 hours, then performing suction filtration, washing the precipitate to be neutral, and then drying the precipitate for 24 hours at 100 ℃; and
(3) and (3) heating the product obtained in the step (2) to 600 ℃ in a tube furnace, roasting for 6 hours in an air atmosphere to obtain a dark brown solid, and then reducing for 3 hours in a hydrogen atmosphere at 300 ℃ to obtain the CuMgAl oxide catalyst.
The catalyst is used for synthesizing 2, 3-butanediol:
2mL of 1, 2-propanediol and 15mL of methanol were added to a batch autoclave, 0.2g of the catalyst prepared by the above method was added, and the autoclave was sealed. Then, the air in the batch type high-pressure reaction kettle is replaced by hydrogen (for multiple times), then the reaction is carried out for 3 hours at the temperature of 210 ℃ under the hydrogen pressure of 2MPa, the reaction is finished and cooled to the room temperature, a filter membrane with the diameter of 0.22 mu m is used for filtering and sampling to prepare a sample, 2,3-butanediol has three stereoisomers, wherein the stereoisomers comprise an internal isomer, the conversion rate of the 1, 2-propanediol is calculated to be close to 58.3 percent by qualitative analysis through gas chromatography (GC-MS), and the selectivity of the 2,3-butanediol reaches 78.8 percent.
Example 7
The Cu-based metal oxide catalyst according to the present application was prepared using the following preparation method:
(1) preparing magnesium nitrate, aluminum nitrate and copper nitrate into mixed aqueous solution according to the molar ratio of 12:4:3, wherein the molar concentrations of the mixed aqueous solution are 0.06mol/L, 0.02mol/L and 0.015mol/L respectively (the volume of the mixed solution is about 150 mL);
(2) dropwise adding the mixed aqueous solution prepared in the step (1) into a sodium carbonate aqueous solution (with the molar concentration of 0.133mol/L) at 65 ℃, stirring while dropwise adding, then dropwise adding a sodium hydroxide solution (1mol/L) to adjust the pH value of the system to 10, then continuously stirring for 1 hour at room temperature, standing and aging for 24 hours, then performing suction filtration, washing the precipitate to be neutral, and then drying the precipitate for 24 hours at 100 ℃; and
(3) and (3) heating the product obtained in the step (2) to 426 ℃ in a tube furnace by a program, and roasting for 12 hours in an air atmosphere to obtain the CuMgAl oxide catalyst.
The catalyst is used for synthesizing 2, 3-butanediol:
2mL of 1, 2-propanediol and 15mL of methanol were added to a batch autoclave, 0.2g of the catalyst prepared by the above method was added, and the autoclave was sealed. Then, the air in the batch type high-pressure reaction kettle is replaced by hydrogen (for multiple times), then the reaction is carried out for 3 hours at the temperature of 210 ℃ under the hydrogen pressure of 2MPa, the reaction is finished and cooled to the room temperature, a sample is prepared by filtering through a 0.22-micron filter membrane, 2,3-butanediol has three stereoisomers, wherein the stereoisomer comprises an internal isomer, the conversion rate of the 1, 2-propanediol is close to 57.74 percent by calculation through qualitative analysis of gas chromatography (GC-MS), and the selectivity of the 2,3-butanediol reaches 70.8 percent.
Example 8
The Cu-based metal oxide catalyst according to the present application was prepared using the following preparation method:
(1) preparing magnesium nitrate, aluminum nitrate and copper nitrate into mixed aqueous solution according to the molar ratio of 20:13:5, wherein the molar concentrations of the mixed aqueous solution are 0.06mol/L, 0.039mol/L and 0.015mol/L respectively (the volume of the mixed solution is about 150 mL);
(2) dropwise adding the mixed aqueous solution prepared in the step (1) into a sodium carbonate aqueous solution (with the molar concentration of 0.133mol/L) at 65 ℃, stirring while dropwise adding, then dropwise adding a sodium hydroxide solution (1mol/L) to adjust the pH value of the system to 10, then continuously stirring for 1 hour at room temperature, standing and aging for 24 hours, then carrying out suction filtration, washing the precipitate to be neutral, and then placing the precipitate at 100 ℃ for drying for 24 hours; and
(3) and (3) heating the product obtained in the step (2) to 550 ℃ in a tube furnace, roasting for 6 hours in an air atmosphere to obtain a dark brown solid, and then reducing for 3 hours in a hydrogen atmosphere at 350 ℃ to obtain the CuMgAl oxide catalyst.
The catalyst is used for synthesizing 2, 3-butanediol:
2mL of 1, 2-propanediol and 15mL of methanol were added to a batch autoclave, 0.2g of the catalyst prepared by the above method was added, and the autoclave was sealed. Then, the air in the batch type high-pressure reaction kettle is replaced by hydrogen (for multiple times), then the reaction is carried out for 3 hours at the temperature of 210 ℃ under the hydrogen pressure of 2MPa, the reaction is finished and cooled to the room temperature, a sample is prepared by filtering and sampling through a 0.22 mu m filter membrane, 2,3-butanediol has three stereoisomers, wherein the stereoisomer comprises one meso isomer, the conversion rate of the 1, 2-propylene glycol is close to 42.99 percent by calculation through qualitative analysis of gas chromatography (GC-MS), and the selectivity of the 2,3-butanediol reaches 58.5 percent.
Example 9
The Cu-based metal oxide catalyst according to the present application was prepared using the following preparation method:
(1) preparing magnesium nitrate, aluminum nitrate and copper nitrate into mixed aqueous solution according to the molar ratio of 20:13:5, wherein the molar concentrations of the mixed aqueous solution are 0.06mol/L, 0.039mol/L and 0.015mol/L respectively (the volume of the mixed solution is about 150 mL);
(2) dropwise adding the mixed aqueous solution prepared in the step (1) into a sodium carbonate aqueous solution (with the molar concentration of 0.40mol/L) at 65 ℃, stirring while dropwise adding, then dropwise adding a sodium hydroxide solution (1mol/L) to adjust the pH value of the system to 10, then continuously stirring for 1 hour at room temperature, standing and aging for 24 hours, then carrying out suction filtration, washing the precipitate to be neutral, and then placing the precipitate at 100 ℃ for drying for 24 hours; and
(3) and (3) heating the product obtained in the step (2) to 550 ℃ in a tube furnace, roasting for 6 hours in an air atmosphere to obtain a dark brown solid, and then reducing for 3 hours in a hydrogen atmosphere at 350 ℃ to obtain the CuMgAl oxide catalyst.
The catalyst is used for synthesizing 2, 3-butanediol:
2mL of 1, 2-propanediol and 15mL of methanol were added to a batch autoclave, 0.05mL of the reaction intermediate formaldehyde was added as an initiator, 0.2g of the catalyst prepared by the above method was added, and the autoclave was sealed. Then, the air in the batch type high-pressure reaction kettle is replaced by hydrogen (for multiple times), then the reaction is carried out for 3 hours at the temperature of 210 ℃ under the hydrogen pressure of 2MPa, the reaction is finished and cooled to the room temperature, a sample is prepared by filtering and sampling through a 0.22 mu m filter membrane, 2,3-butanediol has three stereoisomers, wherein the stereoisomer comprises one meso isomer, the conversion rate of the 1, 2-propylene glycol is close to 21.24 percent by calculation through qualitative analysis of gas chromatography (GC-MS), and the selectivity of the 2,3-butanediol reaches 78.19 percent.
Example 10
The Cu-based metal oxide catalyst according to the present application was prepared using the following preparation method:
(1) preparing calcium nitrate, zirconyl nitrate and copper nitrate into mixed aqueous solution according to a molar ratio of 6:2:1, wherein the molar concentrations of the mixed aqueous solution are 0.06mol/L, 0.02mol/L and 0.01mol/L respectively (the volume of the mixed solution is about 150 mL);
(2) dropwise adding the mixed aqueous solution obtained in the step (1) into an aqueous sodium carbonate solution at 65 ℃ so that the molar concentration of carbonate is 0.53mol/L (10.6g of Na)2CO3The volume of the solution is about 187mL), the molar concentration of calcium is 0.06mol/L, the molar concentration of zirconium is 0.02mol/L, the molar concentration of copper is 0.01mol/L, stirring is carried out while dropwise adding, then sodium hydroxide solution (1mol/L) is dropwise added to adjust the pH value of the system to be 10, then stirring is continued for 1 hour at room temperature, standing and aging are carried out for 24 hours, then suction filtration is carried out, the precipitate is washed to be neutral, and then the precipitate is dried for 24 hours at 100 ℃; and
(3) and (3) heating the product obtained in the step (2) to 550 ℃ in a tubular furnace, roasting for 6 hours in air atmosphere, and reducing the obtained solid for 3 hours in 350 ℃ hydrogen atmosphere to obtain the CuCaZr oxide catalyst.
The catalyst is adopted to synthesize 2, 3-butanediol:
2mL of 1, 2-propanediol and 15mL of methanol were added to a batch autoclave, 0.02mL of hydroxy acetone, which is a reaction intermediate, was added as an initiator, 0.2g of the catalyst prepared by the above method was added, and the autoclave was sealed. Then, the air in the batch autoclave was replaced with hydrogen (several times), and then the reaction was carried out at a hydrogen pressure of 2MPa and a temperature of 210 ℃ for 3 hours, after the completion of the reaction, the reaction was cooled to room temperature, and the sample was obtained by filtration through a 0.22 μm filter membrane, whereby a sample was prepared, and the conversion of 1, 2-propanediol was calculated to be close to 39.1% and the selectivity of 2,3-butanediol was calculated to be 58.16%, since 2,3-butanediol had three stereoisomers including one meso isomer, by qualitative analysis using gas chromatography (GC-MS).
The above-described embodiments of the present application are only preferred embodiments for explaining the present application, and are not limiting to the present application, and those skilled in the art can make modifications without inventive contribution as required after reading the present specification, however, any modifications, equivalents, improvements, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims (10)

  1. A method for preparing a Cu-based metal oxide catalyst, comprising the steps of:
    (1) preparing a mixed aqueous solution of a copper salt, a magnesium salt or a calcium salt and a first metal A salt, wherein the first metal A salt is a salt of a divalent or trivalent metal ion; wherein the molar ratio of Mg or Ca to A is 1.4-6, and the molar content of Cu is 2-60% of the total molar amount of all metal ions;
    (2) dropwise adding the metal salt mixed water solution prepared in the step (1) into a carbonate water solution or an alkali solution at the temperature of 60-70 ℃, dropwise adding the alkali solution to adjust the pH value of the system to 9.5-10.5, preferably 10, continuously stirring at room temperature for 1-5 hours, standing and aging for 18-30 hours, preferably 24 hours, filtering and washing to be neutral, and drying at the temperature of 100-120 ℃ for 12-24 hours; and
    (3) roasting the product obtained in the step (2) at the temperature of 500-600 ℃ for 3-12 hours in an air atmosphere to obtain the Cu-based metal oxide catalyst CuyMgmAnOxOr CuyCamAnOxWherein the ratio of m/n is 1.4-6, y/(m + n + y) is 0.02-0.6, and x is the chemical oxygen demand of the stoichiometric ratio.
  2. 2. The production method according to claim 1, wherein the first metal a salt is at least one selected from a Ca salt, an Al salt, and a Zr salt.
  3. 3. The method of claim 1, wherein the copper, magnesium or calcium salt and the first metal A salt are nitrates.
  4. 4. The method according to claim 1, wherein the step (1) is performed at 60-70 ℃.
  5. 5. The production method according to claim 1, wherein in the step (2),
    the carbonate in the aqueous carbonate solution is at least one selected from sodium carbonate or potassium carbonate, and is preferably sodium carbonate, and
    and dropwise adding the metal salt mixed aqueous solution into a carbonate aqueous solution to enable the molar concentration of carbonate in the system to be 0.5-10 times of the total molar concentration of metal ions.
  6. 6. The production method according to claim 1, wherein in the step (2),
    the alkali in the alkali solution is at least one selected from sodium hydroxide or potassium hydroxide, and is preferably sodium hydroxide, and
    OH in the alkali solution-The molar concentration of the ions is 1-10 times of the total molar concentration of the metal ions in the mixed water solution.
  7. 7. The method of claim 1, further comprising: in the step (3), the product obtained by roasting is reduced in a hydrogen atmosphere at 300 to 400 ℃ for 2.5 to 3.5 hours, preferably 3 hours, and then the Cu-based metal oxide catalyst is obtained.
  8. 8. The Cu-based metal oxide catalyst according to the method for preparing a Cu-based metal oxide catalyst, as recited in any one of claims 1 to 7.
  9. 9. A method for synthesizing a Cu-based metal oxide catalyst produced by the production method according to any one of claims 1 to 7 or 2,3-butanediol using the Cu-based metal oxide catalyst according to claim 8, comprising:
    in the presence of the Cu-based metal oxide catalyst and in a hydrogen atmosphere, carrying out intermittent high-pressure reaction on methanol and 1, 2-propylene glycol for 3-5 hours under the conditions that the gas pressure is 1-3 MPa and the reaction temperature is 190-210 ℃ to obtain the 2, 3-butanediol.
  10. 10. The synthesis process according to claim 9, characterized in that the weight of 1, 2-propanediol represents from 2.5% to 35%, preferably from 7.5% to 15%, of the total weight of the mixture of methanol and 1, 2-propanediol, and
    the reaction temperature was 210 ℃.
CN202210220303.9A 2022-03-08 2022-03-08 Cu-based metal oxide catalyst, preparation method thereof and synthesis method of 2,3-butanediol using same Pending CN114588904A (en)

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CN101306368A (en) * 2008-07-09 2008-11-19 山西大学 Preparation method of butanediol secondary hydrogenation catalyst by butynediol two-step hydrogenation
CN103028403A (en) * 2011-09-30 2013-04-10 北京化工大学 Body type copper-based ester hydrogenation catalyst and preparation method and application thereof
CN103084178A (en) * 2013-01-17 2013-05-08 上海中科高等研究院 Copper-contained hydrotalcite-based catalyst for preparing mixed alcohol by using synthesis gas as well as preparation method and application thereof
US20150166443A1 (en) * 2012-06-29 2015-06-18 Abengoa Bionergía Nuevas Technologías, S. A. Method for obtaining higher alcohols
CN108043403A (en) * 2017-12-07 2018-05-18 中国科学院山西煤炭化学研究所 A kind of synthesis higher alcohols catalyst and preparation method and application
US20190031585A1 (en) * 2017-07-27 2019-01-31 Battelle Memorial Institute Method of converting ethanol to higher alcohols
CN110773174A (en) * 2019-09-24 2020-02-11 浙江大学 Catalyst for preparing gamma-butyrolactone through dehydrogenation of 1, 4-butanediol and preparation method thereof
CN111330582A (en) * 2020-05-06 2020-06-26 济南大学 Preparation method and application of copper-based catalyst

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101306368A (en) * 2008-07-09 2008-11-19 山西大学 Preparation method of butanediol secondary hydrogenation catalyst by butynediol two-step hydrogenation
CN103028403A (en) * 2011-09-30 2013-04-10 北京化工大学 Body type copper-based ester hydrogenation catalyst and preparation method and application thereof
US20150166443A1 (en) * 2012-06-29 2015-06-18 Abengoa Bionergía Nuevas Technologías, S. A. Method for obtaining higher alcohols
CN103084178A (en) * 2013-01-17 2013-05-08 上海中科高等研究院 Copper-contained hydrotalcite-based catalyst for preparing mixed alcohol by using synthesis gas as well as preparation method and application thereof
US20190031585A1 (en) * 2017-07-27 2019-01-31 Battelle Memorial Institute Method of converting ethanol to higher alcohols
CN108043403A (en) * 2017-12-07 2018-05-18 中国科学院山西煤炭化学研究所 A kind of synthesis higher alcohols catalyst and preparation method and application
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CN111330582A (en) * 2020-05-06 2020-06-26 济南大学 Preparation method and application of copper-based catalyst

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